A 2-DIMENSIONAL FLOW SENSOR USING INTEGRATED SILICON SPREADING-RESISTANCE TEMPERATURE DETECTORS

A simple silicon two-dimensional (2D) flow sensor for the measurement of both flow direction and speed is described. By integrating two coup les of silicon spreading-resistance temperature (SRT) sensors in two p erpendicular directions on the surface of a silicon chip, this sensor can detect flow speed and flow direction phi in a full range of 360 de grees. Experimental results confirm theoretical analysis that the outp ut of the sensor increases with the square root of the flow velocity, and the outputs in the two perpendicular directions are proportional t o sin phi and cos phi, respectively. The effects of sensor layout are also discussed. With complete oxide isolation for the SRT sensors, the flow sensor could achieve higher sensitivity by operating above the i ntrinsic temperature of silicon (similar to 150 degrees C), or could b e used to detect fluid flow at a temperature as high as 300 degrees C. (C) 1997 American Institute of Physics.